1. Field of the Invention
This invention relates in general to grinding machinery and in particular to a force feed assembly for a granulator of articles.
2. Description of the Prior Art
In manufacturing plastic articles, such as drinking cups, hamburger cartons, liquid cleaning solution bottles, and the like, a certain percentage will have defects that require them to be rejected. In large high-speed plants, the number of rejects adds up to a large amount of scrap. Many plants have devices for grinding or granulating the rejected articles, reducing them into particles small enough that allows the particles to be converted into raw material for reuse in the forming process. Granulators are also used for metal objects, such as aluminum cans and plastic coated copper wire.
Normally, granulators have a chute with an entry for inserting the articles, and a grinder chamber mounted below. The grinder chamber includes a set of rotor knives that rotate past a stationary bed knife to cut the articles. A perforated screen is mounted below, to allow the particles to fall into a collection chamber when they are cut into small enough pieces. The articles are gravity fed into the grinder chamber. Applicants do not know of any type of feeder mechanism used in this type of granulator for urging articles into the grinder chamber.
One type of granulator uses feed rollers to urge the material into the grinder chamber. However, this type of granulator does not process three dimensional articles, rather granulates thin sheets of plastic scrap material. The feed rollers comprise a pair of rotating pipes, each pipe having small tubes welded to the pipe surface parallel to its axis for urging the sheet material into the grinder chamber. This type of feeder mechanism would not aid in urging light, hollow, three dimensional articles into the grinder chamber.
Various patents for grinding materials disclose feeder mechanisms, including U.S. Pat. Nos. 1,187,242, 416,204 and 3,310,086.